The place-name Lethrie may contain G leth ‘half’, but the absence of early forms makes any interpretation very tentative.

The 1801 Sasine speaks of the ‘Mill of Balgonar or Lethrie’ as if they were one and the same mill; but Ainslie/Fife (1775) and Ainslie/West Fife (1827) both show another mill called Wyldsmill between Balgonar and Lethriemill. The above NGR is from the OS 6 inch 1st edn. (1855).